"""
PEP 302 based plugin loading mechanism, works around the bug in zipimport in
python 2.x that prevents importing from zip files in locations whose paths
have non ASCII characters
"""
import os, zipfile, posixpath, importlib, threading, re, imp, sys
from collections import OrderedDict
from functools import partial

from ebook_converter import as_unicode
from ebook_converter.constants import ispy3
from ebook_converter.customize import (Plugin, numeric_version, platform,
        InvalidPlugin, PluginNotFound)
from ebook_converter.polyglot.builtins import itervalues, reload


__license__ = 'GPL v3'
__copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
__docformat__ = 'restructuredtext en'


def get_resources(zfp, name_or_list_of_names):
    '''
    Load resources from the plugin zip file

    :param name_or_list_of_names: List of paths to resources in the zip file using / as
                separator, or a single path

    :return: A dictionary of the form ``{name : file_contents}``. Any names
                that were not found in the zip file will not be present in the
                dictionary. If a single path is passed in the return value will
                be just the bytes of the resource or None if it wasn't found.
    '''
    names = name_or_list_of_names
    if isinstance(names, (str, bytes)):
        names = [names]
    ans = {}
    with zipfile.ZipFile(zfp) as zf:
        for name in names:
            try:
                ans[name] = zf.read(name)
            except:
                import traceback
                traceback.print_exc()
    if len(names) == 1:
        ans = ans.pop(names[0], None)

    return ans


def get_icons(zfp, name_or_list_of_names):
    '''
    Load icons from the plugin zip file

    :param name_or_list_of_names: List of paths to resources in the zip file using / as
                separator, or a single path

    :return: A dictionary of the form ``{name : QIcon}``. Any names
                that were not found in the zip file will be null QIcons.
                If a single path is passed in the return value will
                be A QIcon.
    '''
    from PyQt5.Qt import QIcon, QPixmap
    names = name_or_list_of_names
    ans = get_resources(zfp, names)
    if isinstance(names, (str, bytes)):
        names = [names]
    if ans is None:
        ans = {}
    if isinstance(ans, (str, bytes)):
        ans = dict([(names[0], ans)])

    ians = {}
    for name in names:
        p = QPixmap()
        raw = ans.get(name, None)
        if raw:
            p.loadFromData(raw)
        ians[name] = QIcon(p)
    if len(names) == 1:
        ians = ians.pop(names[0])
    return ians


_translations_cache = {}


def load_translations(namespace, zfp):
    null = object()
    trans = _translations_cache.get(zfp, null)
    if trans is None:
        return
    if trans is null:
        from ebook_converter.utils.localization import get_lang
        lang = get_lang()
        if not lang or lang == 'en':  # performance optimization
            _translations_cache[zfp] = None
            return
        with zipfile.ZipFile(zfp) as zf:
            try:
                mo = zf.read('translations/%s.mo' % lang)
            except KeyError:
                mo = None  # No translations for this language present
        if mo is None:
            _translations_cache[zfp] = None
            return
        from gettext import GNUTranslations
        from io import BytesIO
        trans = _translations_cache[zfp] = GNUTranslations(BytesIO(mo))

    namespace['_'] = getattr(trans, 'gettext' if ispy3 else 'ugettext')
    namespace['ngettext'] = getattr(trans, 'ngettext' if ispy3 else 'ungettext')


class PluginLoader(object):

    def __init__(self):
        self.loaded_plugins = {}
        self._lock = threading.RLock()
        self._identifier_pat = re.compile(r'[a-zA-Z][_0-9a-zA-Z]*')

    def _get_actual_fullname(self, fullname):
        parts = fullname.split('.')
        if parts[0] == 'calibre_plugins':
            if len(parts) == 1:
                return parts[0], None
            plugin_name = parts[1]
            with self._lock:
                names = self.loaded_plugins.get(plugin_name, None)
                if names is None:
                    raise ImportError('No plugin named %r loaded'%plugin_name)
                names = names[1]
                fullname = '.'.join(parts[2:])
                if not fullname:
                    fullname = '__init__'
                if fullname in names:
                    return fullname, plugin_name
                if fullname+'.__init__' in names:
                    return fullname+'.__init__', plugin_name
        return None, None

    def find_module(self, fullname, path=None):
        fullname, plugin_name = self._get_actual_fullname(fullname)
        if fullname is None and plugin_name is None:
            return None
        return self

    def load_module(self, fullname):
        import_name, plugin_name = self._get_actual_fullname(fullname)
        if import_name is None and plugin_name is None:
            raise ImportError('No plugin named %r is loaded'%fullname)
        mod = sys.modules.setdefault(fullname, imp.new_module(fullname))
        mod.__file__ = "<calibre Plugin Loader>"
        mod.__loader__ = self

        if import_name.endswith('.__init__') or import_name in ('__init__',
                'calibre_plugins'):
            # We have a package
            mod.__path__ = []

        if plugin_name is not None:
            # We have some actual code to load
            with self._lock:
                zfp, names = self.loaded_plugins.get(plugin_name, (None, None))
            if names is None:
                raise ImportError('No plugin named %r loaded'%plugin_name)
            zinfo = names.get(import_name, None)
            if zinfo is None:
                raise ImportError('Plugin %r has no module named %r' %
                        (plugin_name, import_name))
            with zipfile.ZipFile(zfp) as zf:
                try:
                    code = zf.read(zinfo)
                except:
                    # Maybe the zip file changed from under us
                    code = zf.read(zinfo.filename)
            compiled = compile(code, 'calibre_plugins.%s.%s'%(plugin_name,
                import_name), 'exec', dont_inherit=True)
            mod.__dict__['get_resources'] = partial(get_resources, zfp)
            mod.__dict__['get_icons'] = partial(get_icons, zfp)
            mod.__dict__['load_translations'] = partial(load_translations, mod.__dict__, zfp)
            exec(compiled, mod.__dict__)

        return mod

    def load(self, path_to_zip_file):
        if not os.access(path_to_zip_file, os.R_OK):
            raise PluginNotFound('Cannot access %r'%path_to_zip_file)

        with zipfile.ZipFile(path_to_zip_file) as zf:
            plugin_name = self._locate_code(zf, path_to_zip_file)

        try:
            ans = None
            plugin_module = 'calibre_plugins.%s'%plugin_name
            m = sys.modules.get(plugin_module, None)
            if m is not None:
                reload(m)
            else:
                m = importlib.import_module(plugin_module)
            plugin_classes = []
            for obj in itervalues(m.__dict__):
                if isinstance(obj, type) and issubclass(obj, Plugin) and \
                        obj.name != 'Trivial Plugin':
                    plugin_classes.append(obj)
            if not plugin_classes:
                raise InvalidPlugin('No plugin class found in %s:%s'%(
                    as_unicode(path_to_zip_file), plugin_name))
            if len(plugin_classes) > 1:
                plugin_classes.sort(key=lambda c:(getattr(c, '__module__', None) or '').count('.'))

            ans = plugin_classes[0]

            if ans.minimum_calibre_version > numeric_version:
                raise InvalidPlugin(
                    'The plugin at %s needs a version of calibre >= %s' %
                    (as_unicode(path_to_zip_file), '.'.join(map(str,
                        ans.minimum_calibre_version))))

            if platform not in ans.supported_platforms:
                raise InvalidPlugin(
                    'The plugin at %s cannot be used on %s' %
                    (as_unicode(path_to_zip_file), platform))

            return ans
        except:
            with self._lock:
                del self.loaded_plugins[plugin_name]
            raise

    def _locate_code(self, zf, path_to_zip_file):
        names = [x if isinstance(x, str) else x.decode('utf-8') for x in
                zf.namelist()]
        names = [x[1:] if x[0] == '/' else x for x in names]

        plugin_name = None
        for name in names:
            name, ext = posixpath.splitext(name)
            if name.startswith('plugin-import-name-') and ext == '.txt':
                plugin_name = name.rpartition('-')[-1]

        if plugin_name is None:
            c = 0
            while True:
                c += 1
                plugin_name = 'dummy%d'%c
                if plugin_name not in self.loaded_plugins:
                    break
        else:
            if self._identifier_pat.match(plugin_name) is None:
                raise InvalidPlugin((
                    'The plugin at %r uses an invalid import name: %r' %
                    (path_to_zip_file, plugin_name)))

        pynames = [x for x in names if x.endswith('.py')]

        candidates = [posixpath.dirname(x) for x in pynames if
                x.endswith('/__init__.py')]
        candidates.sort(key=lambda x: x.count('/'))
        valid_packages = set()

        for candidate in candidates:
            parts = candidate.split('/')
            parent = '.'.join(parts[:-1])
            if parent and parent not in valid_packages:
                continue
            valid_packages.add('.'.join(parts))

        names = OrderedDict()

        for candidate in pynames:
            parts = posixpath.splitext(candidate)[0].split('/')
            package = '.'.join(parts[:-1])
            if package and package not in valid_packages:
                continue
            name = '.'.join(parts)
            names[name] = zf.getinfo(candidate)

        # Legacy plugins
        if '__init__' not in names:
            for name in tuple(names):
                if '.' not in name and name.endswith('plugin'):
                    names['__init__'] = names[name]
                    break

        if '__init__' not in names:
            raise InvalidPlugin(('The plugin in %r is invalid. It does not '
                    'contain a top-level __init__.py file')
                    % path_to_zip_file)

        with self._lock:
            self.loaded_plugins[plugin_name] = (path_to_zip_file, names)

        return plugin_name


loader = PluginLoader()
sys.meta_path.insert(0, loader)


if __name__ == '__main__':
    from tempfile import NamedTemporaryFile
    from ebook_converter.customize.ui import add_plugin
    from ebook_converter import CurrentDir
    path = sys.argv[-1]
    with NamedTemporaryFile(suffix='.zip') as f:
        with zipfile.ZipFile(f, 'w') as zf:
            with CurrentDir(path):
                for x in os.listdir('.'):
                    if x[0] != '.':
                        print('Adding', x)
                    zf.write(x)
                    if os.path.isdir(x):
                        for y in os.listdir(x):
                            zf.write(os.path.join(x, y))
        add_plugin(f.name)
        print('Added plugin from', sys.argv[-1])